1. Field of the Invention
The invention relates to (1) a hinge mechanism for interconnecting rectangular panels such as door panels and (2) an overhead sectional breakaway door formed of a plurality of rectangular panels connected to each other and disposed adjacent a door opening and including the hinge mechanism on at least the breakaway door panels, whereby the rectangular door panels are movable vertically to open and close the door opening. Channels or tracks are vertically mounted adjacent side edges of the door opening. The rectangular panels may include guide elements such as rollers that are guided within the tracks to enable the door to move vertically. At least the bottommost rectangular panel is a releasable, breakaway panel. The releasable panels are substantially rigid, i.e. free of substantial flexure at least at peripheral regions, and at least the bottommost panel includes a releasable retainer mechanism connected to the panel to retain the panel in position with respect to the tracks during normal or routine movements of the door and for releasing the panel to enable freely swinging movement of the releasable panel with respect to the tracks or channels when a predetermined impact force is applied to the releasable panel. The novel hinge mechanism provides a unique pivotal connection between adjacent panels to enable the panels to pivot in opposite directions, i.e. inwardly and outwardly (or clockwise/counter-clockwise when locking from an end viewpoint) whereby when the panel is impacted to break free of the track in a specific direction, vertical movement or separation of the panels with respect to each other will be accompanied by a simultaneous pivotal movement.
2. Description of Related Art
Overhead doors formed from a plurality of rectangular panels that are hingedly connected to each other, and including rollers which are guided within guide channels or tracks positioned adjacent the side edges of the door opening, arc known in the art. Such overhead doors move vertically with the rollers captured within the channels or tracks. The channels or tracks may curve from a vertical into a horizontal position in a relatively short distance above the door opening, an arrangement known as a standard lift overhead door system. In another arrangement, called a high lift system, the track also curves but over a greater distance above the door opening and ultimately into a horizontal position. In another overhead door arrangement, known as a full vertical lift system, the door panels move straight upwards, or at a gentle angle away from the door.
One of the problems with the known overhead door arrangements is that often the rectangular panels are not moved completely out of the door opening perimeter and the lower or bottommost panel extends just below the horizontal door frame which makes it susceptible to being struck by vehicles or objects, such as forklifts, automobiles, trucks, etc. For example, as the door is opening, vehicular traffic, such as fork lifts, etc., try to go through the door opening prior to the door being completely out of the opening. Similarly, when the door is just beginning to close, and vehicular traffic is unaware of the closing, the door may be struck by the vehicle. Still another problem could arise when the door is closed and is accidentally bumped in the closed position resulting in damage to the door making it inoperative. Thus a need has arisen to design an overhead door system that minimizes the damage to at least the bottommost rectangular panels when struck by motor vehicles or other tall structures that pass through the door opening.
One such breakaway door having a releasable rectangular panel is described in applicant's U.S. Pat. No. 5,727,614, issued on Mar. 17, 1998 and entitled Overhead Door With Releasable Breakaway Panel. The embodiment of FIGS. 1-6 of the above U.S. Pat. No. 5,727,614 (without the spring biasing arrangement 91) may be deemed prior art. Reference should also be made to U.S. Pat. Nos. 4,676,293 (Hanssen), 5,535,805 (Kellogg et al.), and 5,584,333 (Torchetti et al.).
Because standard overhead doors such as garage doors can sustain a great deal of damage, if not completely destroyed, when impacted, the products developed over the past several years address the damage problem in various ways. Many doors have been developed to sustain an impact due to the materials used to make the panel itself. All of the new panels designed to withstand an impact have had to address at least two significant issues. First, the panel had to release from the opening at some predetermined force because no material could be both economically priced and withstand a vehicular force unless it released from the tracking system. Secondly, the panel had to swivel inwardly and outwardly in order to take an impact from both directions.
Two somewhat rectangular shaped panels, such as garage door panels, when pivotally connected to each other cannot pivot in both directions using standard garage door hinges. A standard garage door hinge is very efficient for use on standard garage door applications. The standard hinge is designed to allow the panel to pivot in one direction thereby allowing each independent panel to follow a curve in the track when raising out of the opening. These standard garage doors are not however, manufactured to withstand an accidental impact, from either direction, to the section without anticipated damage discussed above. Double-pinned hinges have been designed for other types (i.e., horizontal swinging about a vertical axis) of door products, such as free-swinging kitchen doors, to allow for two-way pivoting action about a vertical axis, but there is no known automatically adjustable single pin hinge designed for a sectional door that pivots about a horizontal axis.